1. Field of the Invention
Prefabricated floorboards which at their edges are provided with groove and tongue are well known nowadays. As these are very easy to install it is possible for the normal handy man to achieve this. These type of floors can be constituted of massive wood, fibre board or particle board. These are often provided with a surface layer, such as lacquer or some sort of laminate. The boards are most often installed by gluing them together, via their groove and tongue. It is desired to join the separate boards so closely that the joint becomes practically invisible, which increases the moisture resistance radically. The usable life of the installed floor is hereby also increased. In order to achieve a tight joint, it is essential that glue is used excessively. The clearance in the joint will therefore have to be relatively large in order to be able to force the boards together without having to use special equipment due to the forces that would be needed otherwise. A small clearance will cause a hydraulic resistance caused by the glue captured inside the groove during the joining. The clearance needed will, therefore, cause a random discrepancy in the levels between adjacent floorboards. This discrepancy in levels will lead to an increased wear at the joint and that moisture may penetrate the joint. The decorative wear layer, often constituted by lacquer or laminate will hereby often be worn down closest to the joint. The wood fibre will, hereby, be naked closest to the joint, which, in addition to being unsightly, also may cause the fibres to swell when exposed to moisture. This causes the surface layer to rise closest to the edges whereby these edges will be exposed to further wear, which will decrease the useful life of the floor radically.
2. Description of the Related Art
It has, through the present invention, quite unexpectedly been possible to solve the above mentioned problems so that the risk for error during installation is radically reduced, whereby the average usable life of the floor, with a guiding means according to the present invention, is considerably increased. Accordingly, the invention relates to a guiding means at a joint between boards. The joint comprises groove and tongue preferably intended to be joined by means of glue. The tongue includes at least one guiding wedge whereby a fitting clearance between the tongue and the groove includes a first fitting clearance and a second, guiding, fitting clearance. The second, guiding fitting clearance is obtained through the guiding wedges which are arranged parallel to the extension of the joint, whereby the first fitting clearance comprises the main part of the fit and the second, guiding fitting clearance is in the range 0.1-1 mm, while the second, guiding fitting clearance is in the range 0.01-0.2 mm. The tongue of the joint is provided with at least one equalizing recess so that at least one equalizing cavity is formed in the joint, which equalizing cavity receives surplus glue used during the joining. The first fitting clearance is preferably in the range 0.1-0.5 mm, while the second, guiding fitting clearance is in the range 0.2-0.1 mm.
The cross section area of the equalising cavity is preferably at least 50% of the difference in cross section area between the tongue and the groove.
The guiding wedges are according to one alternative embodiment provided with a number of narrow channels arranged perpendicular to the extension of the joint. The distance between the channels preferably is less than 50 mm, most preferably less than 20 mm, while the width of the channels is at least 1 mm.
It is also advantageous to provide the tongue with a number of vents in the form of holes connecting the equalising cavity to the lower side of the tongue. The holes may alternatively connect the equalising cavity to the lower portions of the joint. According to yet another alternative the holes connects the equalising cavity to the lower side of the board.
The guiding means according to the embodiments of the invention forms a part of floor boards which together form a floor. The core of the boards is constituted by a material selected from the group, a fibre board, a particle board and that at least the upper side of the board is constituted by a decorative thermosetting laminate